Bekhorot 28: three things to remember

If a firstborn develops a blemish right before year-end, the owner receives only enough days past the year to complete thirty.
Post-slaughter inspections are valid for bodily blemishes according to Rabbi Yehuda, because only specific eye cataracts alter after death.
Court-authorized expert judges like Rabbi Tarfon are entirely exempt from paying restitution for mistaken rulings that cause monetary loss.